A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the software and data as described below and in the drawing hereto: Copyright (copyright)1999, Libit Signal Processing, Ltd., All Rights Reserved.
The present invention is a multi-access collision based communications system that has a higher capacity than the existing collision-based communications systems.
Collision-based, multi-access protocols are used in a variety of multi-user communications systems, including VSAT systems, 10 Mbbits/sec Ethernet local area networks (LAN), 100 Mbits/sec Ethernet LAN, and wireless networking systems. In such protocols, two or more transmitters may simultaneously transmit in overlapping frequency bands. In such a case, which is termed xe2x80x9csignal collisionxe2x80x9d, the receiver is incapable of detecting the transmitted data, and all the colliding signals are then retransmitted. The capacity of such systems may be degraded by a factor of 2.7 or more due to re-transmissions. There is a need in the art, therefore, to increase throughput in collision-based communications system.
The present invention solves many of the problems described above and many other problems in the communications field, which solutions will become known to those skilled in the art upon reading and understanding the present invention. The present invention is a collision-based multi-access system which recovers informnation involved in collisions by means of receivers jointly detecting the mutually interfering signals, followed by re-transmission of functions of portions of some of the colliding signals. In stead of re-transmission of all the colliding signals, the present invention enables decreasing the amount of re-transmission in the system, and therefore increasing the system throughput. The present invention is also applicable to non-colliding communications systems to correct interference due to noise.